Abstract:
This project began in 1985 at a Warm Temperate SubTropical site in Australia. The soil at the site is classified as a Vertisol. There are four rotations: cotton-cotton (until 1991), wheat-cotton (until 1991), cowpea (1993 only), fallow (1993 only). All plots were sown to cotton 1994-95 and 1995-96. The treatments on each are: Tillage: Disc followed by chisel followed by ridging, and, Minimum ... till: Reshaping of ridges with some shallow cultivation.

The measurments made (data available), frequency, and methodology are as follows:

Time zero soil measurements taken. Details of time zero sample are given in Constable et al. (1992) - see reference list. Details of soil sampling method: Other procedures in past but current is as follows: Spade - all subplots 14-28 locations. Soil pit - to 1.5m depth, one location on each subplot. Soil is separated into layers. Details of measuring depths and soil layers: 0-15, 15-30, 30-45, 45-60 cm from each subplot (36 subplots in the trial).

Description:
This url links to the GCTE-SOMNET home page where additional project information and methodology can be obtained. This site is currently in a datasharing phase of the network where actual data will become available shortly, at different levels of accessibility. Please follow this link for more information.

Width of smallest plot is 12 m Length of smallest plot is 175 m Width of largest plot is 20 m Length of largest plot is 175 m Slope: 0.5% . Shape: Uniform Details of direction of cultivation: Parallel to long-axis of plots ... Width of Bare Strip around plot: 6-10m Width of Discard Strip around plot: 2-3m Details of homogeneity of the plots: Small increase in clay content going across the field.

b) Details of replication, randomization and controls

There are at least 4 replicates in the experiment. Tillage/Cropping system in RCB; with crops sown in 1993 as sub-plots in a split plot design. Maximum till/continuous cotton since 1985 are used as control plots in this project.